Device for delivering non-biodegradable bulking composition to a urological site

ABSTRACT

A device for delivery of a biocompatible polymer composition for treatment of urinary incontinence provides for delivery of biocompatible polymer material and a solidification agent through two lumens. The delivery device provides better control of the precipitation of the polymer in the periurethral tissue and detachment of the precipitated mass from the delivery device. The medical device includes a needle having a lumen and an inner cannula positioned within the needle lumen and movable longitudinally in the needle lumen from an extended position to a withdrawn position to sheer or cut the delivered mass of polymer material away from the needle tip.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a medical device, and more particularly, theinvention relates to a medical device for delivering a non-biodegradablebulking composition to a urological site to treat urinary incontinence.

2. Brief Description of the Related Art

Urinary incontinence is an extremely common problem especially in women.In particular, many women suffer from stress incontinence. In thiscondition, the pelvic-floor tissues which support the urethra areweakened by, for example, childbirth or obesity. As a result, whenpressure is exerted on these tissues by coughing, lifting, etc., urineis involuntarily discharged from the bladder through the urethra.

The initial treatment for stress incontinence typically consists ofexercises to strengthen the pelvic-floor muscles. If these exercise areineffective, open surgical repair of the bladder neck is oftenattempted. However, such surgical repair procedures are not successfulfor all patients. Moreover, there are always certain risks associatedwith open surgical procedures, such as infection, risks of anesthesia,etc.

As an alternative to surgical repair, urinary incontinence has beentreated by periurethral injection therapy, in which a substance isinjected into the tissue surrounding the urethra, i.e., the periurethraltissue, to add bulk to this tissue. The aim of this treatment is torestore the proximal urethra to its proper normally closed condition andto keep it closed during coughing, straining, or exercise. The injectedsubstance compresses the urethra at the level of the bladder neck thusimpeding the involuntary flow of urine from the bladder.

Many injectable substances have been tried for this purpose with varyingresults. For example, in the first half of the twentieth centurysclerosing solutions, such as sodium morrhuate or cod liver oil wereinjected into the anterior vaginal wall. An inflammatory responsedeveloped with secondary scarring which resulted in compression of theincompetent urethra. Although this material was successful in curingincontinence in some patients, complications included pulmonaryinfarction and cardiac arrest. Similarly, paraffin and other sclerosingsolutions have been tried with poor results.

More recently, polytetrafluoroethylene particles (TEFLON™, POLYTEF™)have been used as an injectable material for the correction of urinaryincontinence with a success rate of from 30% to 86% in some studies.However, these particles have subsequently been demonstrated to generateforeign body granulomas and to migrate to distant organs, such as thelungs, liver, spleen and brain. Accordingly, the use ofpolytetrafluoroethylene particles is currently disfavored.

Another injectable material that has been used recently for thetreatment of urinary incontinence is glutaraldehyde cross-linked bovinedermal collagen. However, a major problem associated with the use ofcollagen materials is the tendency of the implant to decrease in volumeover time thereby necessitating retreatment. In addition, collagen hasbeen associated with adverse immune responses and allergic reactions tobovine dermal collagen have been described.

Various other injectable substances have been reported or proposed asimplant materials for the treatment of bladder conditions, such asvesicoureteral reflux. These substances include polyvinyl alcohol foam,glass particles, a chondrocyte-alginate suspension, and a detachablesilicone balloon.

In addition to the various problems associated with many of thesubstances used to treat urinary incontinence, the methods currentlyemployed for delivering injectable materials to the periurethral tissuehave certain disadvantages. In particular, the amount of materialnecessary to compress the urethra must typically be estimated byobserving the compression of the urethra wall using a cystoscope orendoscope. If an insufficient amount of material is injected in thefirst procedure, top-up injections administered in subsequent proceduresmay be necessary. In addition, the materials which are delivered may beabsorbed by the body over time requiring retreatment. Other materialswhich are used are hydrateable and swell within the body causingdifficulty in predicting a final size of the injected material.

U.S. Pat. Nos. 5,755,658 and 5,785,642, which are incorporated herein byreference in their entirety, describe methods of delivering acomposition comprising a biocompatible polymer and a biocompatiblesolvent to the periurethral tissue. The biocompatible solvent ismiscible or soluble in the fluid of the periurethral tissue and, uponcontact with these fluids, the biocompatible solvent quickly diffusesaway. Upon diffusion of the solvent, the biocompatible polymerprecipitates to form an occlusion in the periurethral tissue whichcompresses the urethra thereby preventing or reducing the involuntaryleakage of urine from the bladder.

However, there are certain drawbacks to the use of conventional deliverysystems with the biocompatible polymer composition. In particular, thebiocompatible polymer composition is injected into the periurethraltissue as a flowable composition which may not solidify instantaneously.Accordingly, it would be desirable to provide faster solidification andbetter control of the delivery of the biocompatible polymer composition.It would also be desirable to provide these advantages for othercompositions which are delivered as two liquids to form a solid.

SUMMARY OF THE INVENTION

The present invention relates to a medical device for delivery of abiocompatible polymer composition to the periurethral tissue to treaturinary incontinence.

In accordance with one aspect of the present invention, a medical deviceincludes a needle and an inner cannula positioned within the needlelumen and movable longitudinally in the needle lumen. The inner cannulahas a lumen for delivering a first fluid and the needle has a lumen fordelivering a second fluid. The inner cannula has a cannula tipconfigured to detach a mass from the needle when the inner cannula ismoved from an extended position at which the cannula tip extends from adistal end of the needle to a withdrawn position at which the cannulatip is within the needle lumen.

In accordance with an additional aspect of the present invention, amedical device includes an inner cannula, an outer cannula coaxiallysurrounding the inner cannula, an injection hub connected to the innerand outer cannulas, and a movable piston within the injection hub. Thepiston is connected to the inner cannula for moving the inner cannulawithin the outer cannula, wherein the movable piston is actuated by adelivered fluid which is delivered through the inner or outer cannula.

In accordance with a further aspect of the invention, a device fordelivering non-biodegradable bulking composition to a urological siteincludes a needle, an inner cannula longitudinally movable within theneedle, the inner cannula having a distal end with a trumpet shaped tip,and an injection hub connected to the needle and inner cannula fordelivery of first and second fluids through the needle and innercannula.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tothe preferred embodiments illustrated in the accompanying drawings, inwhich like elements bear like reference numerals, and wherein:

FIG. 1 is a perspective view of one embodiment of a needle tip accordingto the present invention with an inner cannula in an extended positionfor delivery of the biocompatible polymer composition;

FIG. 2 is a cross section taken along line 2—2 of FIG. 1;

FIG. 3 is a perspective view of the needle tip of FIG. 1 with the innercannula in a withdrawn position for detachment of the biocompatiblepolymer mass;

FIG. 4 is a cross section taken along line 4—4 of FIG. 3;

FIG. 5 is a side cross sectional view of an injection device accordingto the present invention;

FIG. 6 is a perspective view of a second embodiment of a needle tipaccording to the present invention with the inner cannula in an extendedposition;

FIG. 7 is a cross section taken along line 7—7 of FIG. 6;

FIG. 8 is a perspective view of a third embodiment of a needle tipaccording to the present invention with the inner cannula in an extendedposition;

FIG. 9 is a cross section taken along line 9—9 of FIG. 8;

FIG. 10 is a perspective view of a fourth embodiment of a needle tipaccording to the present invention with the inner cannula in an extendedposition;

FIG. 11 is a cross section taken along line 11—11 of FIG. 10;

FIG. 12 is a perspective view of a fifth embodiment of a needle tipaccording to the present invention with the inner cannula in an extendedposition;

FIG. 13 is a side cross sectional view of the embodiment of FIG. 12taken long line 13—13;

FIG. 14 is a perspective view of a sixth embodiment of a needle tipaccording to the present invention with the inner cannula in an extendedposition;

FIG. 15 is a side cross sectional view of the embodiment of FIG. 14taken along line 15—15;

FIG. 16 is a side cross sectional view of the embodiment of FIG. 15 withthe inner cannula in a withdrawn position for detachment of the solidmass from the needle tip; and

FIG. 17 is a side cross sectional view of an alternative embodiment ofthe injection device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention involves a device for treatment of urinary incontinence inmammals by delivering sufficient amounts of a composition comprising abiocompatible polymer and a biocompatible solvent to the periurethraltissue under conditions such that a polymer precipitate forms in situ inthe periurethral tissue. This polymer precipitate compresses theurethral opening thereby affording increased outlet resistance andreducing urinary incontinence in the mammal.

A device for delivery of the biocompatible polymer composition accordingto the present invention provides for delivery of a solidification agentin addition to the polymer material. The solidification agent isdelivered with the polymer material to provide better control of theprecipitation of the polymer in the periurethral tissue. Without thedelivery of the solidification agent, the polymer material may solidifyslowly which may allow the polymer to pass backward into the needleentry channel. The polymer may also adhere itself to the needle tipmaking needle withdrawal difficult.

When the polymer material is adhered to the needle tip, upon withdrawalof the needle, some of the polymer material may be dragged out of theimplant site along with the needle. The device according to the presentinvention provides a plurality of needle tips for detachment of asolidified or partially solidified polymer mass from the tip of theneedle. The needle tips detach the solidified mass by moving an innercannula with respect to an outer cannula to shear or cut the mass awayfrom the needle tip.

As shown in the embodiment of FIGS. 1-4, a delivery needle 10 includesan angled piercing tip 12 and an inner cannula 14. A distal end of theinner cannula 14 has a trumpet shaped tip 16. The inner cannula 14 ismovable from the extended position illustrated in FIGS. 1 and 2 to awithdrawn position illustrated in FIGS. 3 and 4.

In use, once the needle 10 is placed at an injection site in theperiurethral tissue, the inner cannula 14 is moved to the extendedposition as shown in FIG. 1 for injection of the polymer materialthrough an outer lumen 20 between the inner surface of the needle 10 andthe outer surface of the inner cannula 14. Once the polymer injection iscompleted, the inner cannula 14 is withdrawn as illustrated in FIGS. 3and 4. During withdrawal of the inner cannula 14, an edge of the trumpetshaped tip 16 cuts or shears the polymer material against an innersurface of the needle tip 12 detaching the precipitated solid mass ofpolymer material from the needle tip and allowing the needle tip to beeasily withdrawn from the injection site. A solidification agent, suchas saline, is injected through the inner lumen 22 of the inner cannula14 after delivery of the polymer material is complete. Thesolidification agent both solidifies the polymer material and aids inseparating the polymer from the needle. The solidification agent mayalso be delivered before or during delivery of the polymer material.

FIG. 5 illustrates an injection hub 30 of the present invention which isprovided for delivery of fluids to the outer and inner lumens 20, 22 ofthe needle 10 and inner cannula 14 (shown in FIGS. 1-4). The injectionhub 30 includes a body 32 having first and second fluid injection ports34, 36 for delivery of first and second fluids. The needle 10 is fixedto the body 32 by a distal sleeve 38. The distal sleeve 38 has a firstend 40 which is fixed to the needle 10 and a second end 42 which issecured to the injection hub body 32. Contained within the distal sleeve38 is a compression spring 44 for providing a proximal bias to a piston50.

The piston 50 is fixed to the inner cannula 14 by a sleeve 52.Longitudinal motion of the piston 50 inside the body 32 provides motionof the inner cannula 14 with respect to the needle 10. Thesolidification agent is delivered through the first injection port 34and through a first opening 54 in the piston 50 into the inner lumen 22of the inner cannula 14. The polymer material is delivered from thesecond injection port 36 and through a second opening 56 in the piston50 to the outer lumen 20 between the needle 10 and the inner cannula 14.

In the position illustrated in FIG. 5, the piston 50 is biased forwardby fluid pressure on the piston created by delivery of the polymermaterial through the second fluid injection port 36. The injectionpressure of the polymer material advances the piston 50 which in turnadvances the trumpet shaped tip 16 to the extended position. Stoppingthe injection of the polymer material into the second fluid injectionport 36 relieves the forward pressure on the piston 50. With the forwardpressure removed, the compression spring 44 returns the piston 50 andthe trumpet shaped tip 16 of the inner cannula 14 to a retractedposition.

The withdrawal of the trumpet shaped tip 16 into the needle 10 detachesand separates the polymer material from the needle tip 12. Thesolidification agent is preferably injected through the inner lumen 22after withdrawal of the trumpet shaped tip 16. The solidification agentinjection insures that the polymer material is precipitated to a solidat an area adjacent the needle entry channel before the needle assemblyis withdrawn from the injection site to allow the polymer material to bedetached from the needle tip and prevent the polymer material frompassing into the needle entry channel once the needle has beenwithdrawn. The severing of the polymer material below the tissue surfaceprevents infection and/or non-healing of the tissue surface which mayoccur when the polymer material extends to or through the tissuesurface.

A plurality of O-rings 60 are provided in the injection hub 30 betweenthe body 32 and the piston 50. The O-rings contain and isolate thefluids which are injected through the first and second injection ports34, 36. An O-ring retainer plate 62 is also provided which retains thedistal most O-ring in place inside the piston 50.

FIGS. 6 and 7 illustrate an alternative embodiment of a needle 70 havingan angled needle tip 72 and an inner cannula 74 with a disk shaped tip76. The disk shaped tip 76 has an outer diameter which larger than anouter diameter of a remainder of the inner cannula 74 and is less thanor equal to the inner diameter of the needle 70. The disk shaped tip 76has blunt rounded edges. When the inner cannula 74 is moved from theextended position of FIGS. 6 and 7 to a retracted position, the diskshaped tip 76 separates the polymer mass from the needle tip 72 bycutting or shearing of the polymer mass between the disk shaped tip 76and the inner surface of the needle tip 72. The disk shaped tip 76provides the advantages of the trumpet shaped embodiment of FIGS. 1-4with the additional advantage of preventing secondary cutting orpiercing of soft tissue when the disk shaped tip 76 is extended from theend of the needle 70.

FIGS. 8 and 9 illustrate an alternative embodiment of a needle 90 havinga tip 92 and a movable inner cannula 94 with a trocar tip 96. The trocartip 96 has a plurality of bevels 98 forming a sharp cutting tip whichcan be used to cut through firm tissue which would prevent the trocartip 96 from being advanced out of the needle 90. The trocar tip 96 hasan outer diameter which larger than an outer diameter of a remainder ofthe inner cannula 94 and is less than or equal to the inner diameter ofthe needle 90. When the inner cannula 94 is moved from the extendedposition of FIGS. 8 and 9 to a retracted position, the trocar tip 96separates the polymer mass from the needle tip 72 by cutting or shearingof the polymer mass between the trocar tip and the interior of theneedle tip 92.

FIGS. 10 and 11 illustrate another embodiment of a needle 100 having anangled needle tip 102 and a movable inner cannula 104 with an enlargedangled cannula tip 106. As in the embodiment of FIGS. 8 and 9, theangled cannula tip 106 provides a sharp cutting tip which can be used tocut through firm tissue which would prevent the inner cannula 104 frombeing advanced from the needle 90. The angled cannula tip 106 has anouter diameter which is larger than an outer diameter of a remainder ofthe inner cannula 104 and is less than or equal to the inner diameter ofthe needle 100. A rounded shoulder 108 is provided on the inner cannula104 proximal of the distal end of the cannula. When the inner cannula104 is withdrawn into the needle 100, the shoulder 108 traps and shearsthe polymer mass between the shoulder and the needle tip 102 separatingthe polymer mass from the needle tip 102.

FIGS. 12 and 13 illustrate an embodiment of a needle 110 having anangled needle tip 112 and an inner cannula 114. The inner cannula 114has a pointed tip 116 and a side opening 118 at a location just proximalthe pointed tip. The pointed cannula tip 116 may be either blunt orsharp. The needle 110 has a side opening 120 proximal of the needle tip112 at the location of a tapered portion 122 of the needle. Inoperation, a first fluid is delivered through a lumen 124 of the cannula114 and out of the cannula side opening 118. A second fluid is deliveredthrough an annular lumen 126 between the needle 110 and the innercannula 114. According to one embodiment, the first fluid is a bulkingagent including a polymer and a solvent and the second fluid is asolidification agent. For treatment of urinary incontinence, the polymermaterial is preferably delivered through the inner cannula 114 and thesolidification agent is delivered through the side opening 120 of theneedle 110. The location of the side opening 120 of the needle may bearranged to be at or near the site where the needle 110 enters thetissue. This will assure complete solidification of the polymer materialat the needle entry point and will prevent polymer material fromextending out of the tissue and preventing healing or causing infection.

In the embodiment of FIGS. 12 and 13, the inner cannula 114 fits withina portion of the needle 110 distal of the taper 122 with a fit whichsubstantially prevents fluid from passing between the needle and theinner cannula causing the fluid passing through the annular lumen 126 toexit through the opening 120 in the side wall of the needle. When theinner cannula 114 is retracted into the needle 110, the polymer mass iscut or sheared between the needle tip 112 and the edges of the cannulaside opening 118.

FIGS. 14-16 illustrate an embodiment of a needle 110′ similar to that ofFIGS. 12 and 13 in which the needle tip 112′ and cannula tip 116′ areboth formed at the same angle. The point of the cannula tip 116′ may beused for penetrating tissue as the inner cannula 114′ is advanced out ofthe needle 110′. FIG. 16 illustrates the inner cannula 114′ in theretracted needle inserting position. As can be seen in FIG. 16, duringinsertion of the needle tip 112′ the inner cannula 114′ can bepositioned to prevent coring of tissue with the needle.

FIG. 17 illustrates an alternative embodiment of an injection hub 130.The injection hub 130 is particularly designed for use with the needles110, 110′ of FIGS. 12-16 in which the polymer material is deliveredthrough the center lumen 124 of the inner cannula 114 and thesolidification agent is delivered through the annular lumen 126 betweenthe needle and the inner cannula. The injection hub 130 includes a body132 having a first fluid injection port 134 for injection of the polymermaterial and a second fluid injection port 136 for injection of thesolidification agent. The needle 110 is fixed to the body 132 by adistal sleeve 138. Contained within the distal sleeve 138 is acompression spring 144 for providing a proximal bias to a piston 150.

The piston 150 is fixed to the inner cannula 114. Longitudinal motion ofthe piston 150 inside the body 132 provides motion of the inner cannula114 with respect to the needle 110. The polymer material is deliveredthrough the first injection port 134 and through a central opening 154in the piston 150 into the inner lumen 124 of the inner cannula 114. Thesolidification agent is delivered from the second injection port 136 andthrough a side opening 156 in the piston 150 to the outer annular lumen126 between the needle 110 and the inner cannula 114.

In the position illustrated in FIG. 17, the piston 150 is biased forwardby fluid pressure on the piston created by delivery of the polymermaterial through the first fluid injection port 134. The injectionpressure of the polymer material advances the piston 150 which in turnadvances the cannula 114 to the extended position. Stopping theinjection of the polymer material into the first fluid injection port134 relieves the forward pressure on the piston 150. With the forwardpressure removed, the compression spring 144 returns the piston 150 andthe inner cannula 114 to a retracted position detaching the polymermaterial from the needle tip 112.

The solidification agent may be injected through the outer annular lumen126 before, during, and/or after delivery of the polymer material. In apreferred embodiment the solidification agent is delivered after thepolymer material. The solidification agent injection insures that thepolymer material is precipitated to a solid at an area substantiallyadjacent a site where the needle 110 enters the tissue.

A plurality of O-rings 160 are provided in the injection hub 130 betweenthe body 132 and the piston 150. The O-rings contain and isolate thefluids which are injected through the first and second injection ports134, 136. An O-ring retainer plate 162 is also provided which retainsthe distal most O-ring in place inside the piston 150.

The device according to the present invention is preferably designed foruse with a cytoscope or other endoscope. The length of the needle 10will vary depending on the application, however, the needle length ispreferably about 15 to about 225 cm.

The polymeric compositions used in this invention are preferablynonbiodegradable and, accordingly, do not substantially decrease involume over time. Moreover, the injection process provides for acoherent mass, not particulates, which mass is nonmigratory.

The polymeric compositions may optionally include one or more contrastagent. The contrast agent permits monitoring of the injection byconventional methods while it is taking place to ensure that it is beingcarried out properly. The contrast agent also allows monitoringpost-injection by conventional methods to ensure correct placement ofthe mass months or even years after injection. Conventional monitoringmethods include, by way of example, fluoroscopy, ultrasound, and in somecases visual detection.

Although the present invention has been described for use in deliveringa bio-compatible polymer which solidifies in periurethral tissue toprovide treatment of urinary incontinence, the injection device of thepresent invention may also be used for treatment of other conditionssuch as urinary reflux. A method of treating urinary reflux is describedin U.S. Pat. No. 5,958,444 which is incorporated herein by reference inits entirety. The injection device of the present invention may also beused for delivery of other fluids. For example, the system may be usedfor delivery of a two-agent combination where one agent is a catalystthat enables solidification of the other agent (i.e., epoxy).

While the invention has been described in detail with reference to thepreferred embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made and equivalentsemployed, without departing from the present invention.

What is claimed is:
 1. A medical device comprising: a needle having alumen; and an inner cannula positioned within the needle lumen andmovable longitudinally in the needle lumen, the inner cannula having alumen for delivering a first fluid to the patient and the needle lumenarranged for delivering a second fluid to a patient, the inner cannulahaving a cannula tip configured to detach a mass from the needle whenthe inner cannula is moved from an extended position at which thecannula tip extends from a distal end of the needle to a withdrawnposition at which the cannula tip is within the needle lumen, whereinthe inner cannula is movable by fluid pressure.
 2. The medical device ofclaim 1, wherein the cannula tip is a disk shaped tip.
 3. The medicaldevice of claim 1, wherein the cannula tip is an angled needle shapedtip.
 4. The medical device of claim 1, wherein the cannula tip includesa side opening for delivering the first fluid to the patient and theside opening is configured to cut or shear a mass away from the distalend of the needle when the cannula is moved from the extended positionto the withdrawn position.
 5. The medical device of claim 1, furthercomprising an injection hub connected to the needle and the innercannula and configured to deliver the first fluid though the lumen ofthe inner cannula and the second fluid between an inner surface of theneedle and an outer surface of the inner cannula.
 6. The medical deviceof claim 1, further comprising a supply of injectable material forcontrolling urinary incontinence connected to the needle.
 7. The medicaldevice of claim 6, further comprising a supply of a secondary fluidconnected to the inner cannula.
 8. A medical device comprising: a needlehaving a lumen; and an inner cannula positioned within the needle lumenand movable longitudinally in the needle lumen, the inner cannula havinga lumen for delivering a first fluid to the patient and the needle lumenarranged for delivering a second fluid to a patient, the inner cannulahaving a cannula tip configured to detach a mass from the needle whenthe inner cannula is moved from an extended position at which thecannula tip extends from a distal end of the needle to a withdrawnposition at which the cannula tip is within the needle lumen, whereinthe cannula tip is a trumpet shaped tip.
 9. The medical device of claim8, wherein the trumpet shaped tip of the inner cannula is configured tocut or shear a mass away from the distal end of the needle when thecannula is moved from the extended position to the withdrawn position.10. A medical device comprising: a needle having a lumen; and an innercannula positioned within the needle lumen and movable longitudinally inthe needle lumen, the inner cannula having a lumen for delivering afirst fluid to the patient and the needle lumen arranged for deliveringa second fluid to a patient, the inner cannula having a cannula tipconfigured to detach a mass from the needle when the inner cannula ismoved from an extended position at which the cannula tip extends from adistal end of the needle to a withdrawn position at which the cannulatip is within the needle lumen, wherein the cannula tip has a diameterlarger than a remainder of the inner cannula.
 11. A medical devicecomprising: a needle having a lumen; an inner cannula positioned withinthe needle lumen and movable longitudinally in the needle lumen, theinner cannula having a lumen for delivering a first fluid to the patientand the needle lumen arranged for delivering a second fluid to apatient, the inner cannula having a cannula tip configured to detach amass from the needle when the inner cannula is moved from an extendedposition at which the cannula tip extends from a distal end of theneedle to a withdrawn position at which the cannula tip is within theneedle lumen; and an injection hub connected to the needle and the innercannula and configured to deliver the first fluid though the lumen ofthe inner cannula and the second fluid between an inner surface of theneedle and an outer surface of the inner cannula, wherein the injectionhub includes a fluid actuated piston connected to the inner cannula. 12.The medical device of claim 11, wherein the injection of the secondfluid into the injection hub actuates the piston.
 13. The medical deviceof claim 11, wherein the injection of the first fluid into the injectionhub activates the piston.
 14. A medical device comprising: a needlehaving a lumen; an inner cannula positioned within the needle lumen andmovable longitudinally in the needle lumen, the inner cannula having alumen for delivering a first fluid to the patient and the needle lumenarranged for delivering a second fluid to a patient, the inner cannulahaving a cannula tip configured to detach a mass from the needle whenthe inner cannula is moved from an extended position at which thecannula tip extends from a distal end of the needle to a withdrawnposition at which the cannula tip is within the needle lumen; and aninjection hub having a movable member connected to the inner cannula,such that injection of one of the first and second fluids into the hubmoves the movable member and the inner cannula.
 15. A fluid deliverydevice comprising: an inner cannula; an outer cannula coaxiallysurrounding the inner cannula; an injection hub connected to the innerand outer cannulas; and a movable piston within the injection hub, thepiston connected to the inner cannula for moving the inner cannulawithin the outer cannula, wherein the movable piston is actuated by adelivered fluid which is delivered through the inner or outer cannula.16. The fluid delivery device of claim 15, wherein the movable pistonhas a spring for biasing the piston to a first position in which theinner cannula is withdrawn.
 17. The fluid delivery device of claim 16,wherein the movable piston has a second position in which the innercannula is extended and fluid pressure of the delivered fluid moves thepiston from the first position to the second position.
 18. A device fordelivering non-biodegradable bulking composition to a urological site,the device comprising: a needle; an inner cannula longitudinally movablewithin the needle, the inner cannula having a distal end with anenlarged tip configured to detach a mass from the needle when theenlarged tip is moved into the needle; and an injection hub connected tothe needle and inner cannula for delivery of first and second fluidsthrough the needle and inner cannula.
 19. The device of claim 18,further comprising a supply of injectable material for controllingurinary incontinence connected to the needle.
 20. The device of claim19, further comprising a supply of a solidification agent connected tothe inner cannula.
 21. The medical device of claim 18, wherein theenlarged tip of the inner cannula has an outer diameter larger than anouter diameter of a remainder of the cannula.
 22. The medical device ofclaim 18, wherein the enlarged tip of the inner cannula is configured toseparate a delivered mass from the distal end of the needle when thecannula is moved from an extended position to a withdrawn position bycutting or shearing.
 23. The medical device of claim 18, wherein theinner cannula is movable by fluid pressure.
 24. The medical device ofclaim 18, wherein the enlarged tip is a trumpet shaped tip.
 25. Themedical device of claim 18, wherein the enlarged tip is a disk shapedtip.